Japanese Unexamined Patent Publication No. 2008-25082 discloses a process for producing a non-woven fabric, which at least has surface irregularities and allows permeation of a prescribed liquid such as body waste, by emitting air from an upper side onto a fiber web supported from a lower side by a prescribed air-permeable support member to move the fibers that compose the fiber web. It is taught therein that, when producing this non-woven fabric on a production line, the non-woven fabric is formed by increasing the content of fibers oriented in a lengthwise (longitudinal) direction (longitudinally oriented fibers) as a method of increasing resistance of the surface irregularities to deformation caused by line tension (Paragraph [0047]).
Japanese Unexamined Patent Publication (Translation of PCT Application) No. H10-502000 discloses an absorbent article provided with a liquid-permeable surface sheet on a skin side of an absorbent layer. A cover layer having corrugations on a support layer is provided in the absorbent article, leakage of body fluid can be prevented by these corrugations, and comfort when wearing is increased by the flexibility of the corrugations.